1. Field of the Invention
The invention relates to a speech recognition systems, and more particularly, to a method and related device for processing touch commands on a touch-sensitive screen and voice commands in parallel.
2. Description of the Prior Art
Global Positioning System (GPS) based navigation devices are well known and are widely employed as in-car navigation devices. Common functions of a navigation device include providing a map database for generating navigation instructions that are then shown on a display of the navigation device. These navigation devices are often mounted on or in the dashboard of a vehicle using a suction mount or other mounting means.
The term “navigation device” refers to a device that enables a user to navigate to a pre-defined destination. The device may have an internal system for receiving location data, such as a GPS receiver, or may merely be connectable to a receiver that can receive location data. The device may compute a route itself, or communicate with a remote server that computes the route and provides navigation information to the device, or a hybrid device in which the device itself and a remote server both play a role in the route computation process. Personal GPS navigation devices are not permanently integrated into a vehicle but instead are devices that can readily be mounted in or otherwise used inside a vehicle. Generally (but not necessarily), they are fully self-contained—i.e. include an internal GPS antenna, navigation software and maps and can hence plot and display a route to be taken.
A prior art personal navigation devices typically has a touch-sensitive screen for accepting touch input from a user. In addition, the personal navigation device may also have a microphone for accepting voice input from the user, as well as a speech recognition engine for processing the voice input and determining whether a voice command was given to the personal navigation device.
A common problem with speech recognition systems is that they need endpoint indicators at the beginning and the ending of the voice commands so that the speech recognition systems can focus only on the relevant phrases of the speech. In noisy environments such as in a vehicle, the large amount of noise caused by the vehicle, the radio, or by talking passengers makes it difficult for a personal navigation device to properly and correctly analyze voice commands. For this reason, many personal navigation devices allow the user to indicate when the voice command is about to start and when it has ended.
With some devices, a special button is used to tell the device when the voice command has started or has ended. In the case of a personal navigation device, the user may also communicate with the personal navigation device via a remote control. However, using a remote control or an extra button on the device makes the product significantly more expensive. Furthermore, using a soft button on the screen of the personal navigation device is not ideal because the user needs the soft button to have a large area, so as to make for a large target, since the user is operating the personal navigation device while driving. In addition, requiring the user to search for a special soft button on the screen before issuing the voice command defeats the objective of speech recognition if the user is distracted by the process of entering the voice command.
Using an on-screen soft button is also prone to error if the screen has other functions that can be performed which may be inadvertently pressed. This may cause the user to have to spend even more time reversing or undoing commands that were mistakenly made, leading to a more dangerous situation while the user is driving.
Therefore, there is a need for a simple and cost effective way for a user to indicate endpoints before and after a voice command without the need for accuracy in pressing a soft button or a costly hardware button while still allowing the use of the screen for command entry in the case that the user is not occupied with other tasks.